NFS cache misses after upgrading to 11.1 from 10.3

[Niels Kobschaetzki]

Hi,

recently I upgraded a machine from 10.3-Prerelease to 11.1-release. Since then I see a huge difference in nfs cache misses, especially getattr-misses compared to identical configured machines that are still on 10.3. When I do an nfsstat -m the options are identical. 
This leads too less performance and less happy end users. Is there any regression known? Any defaults that changed? Anything else I should know about that could lead to this behavior?

I am grateful for any hint. 
Niels